1. Field of Invention
The present invention relates to a display device and a timepiece.
2. Description of Related Art
A display device according to the related art as depicted in Japanese Unexamined Patent Appl. Pub. JP-A-2007-133182 bonds the terminal portions of a wiring board overlapping the conductor portions of the display panel disposed outside the display area. These conductor portions and wiring board each have a plurality of pins, and adhesion by an anistropic conductive film is used to connect the pins of the conductor portion with the pins of the wiring board.
The display panel has a top substrate, a transparent electrode formed on the top substrate, a bottom substrate on which the pixel electrodes are formed, and an image forming layer including liquid crystals or electrophoretic particles rendered between the transparent electrode and the pixel electrodes. The image forming layer is sealed by epoxy, for example, disposed along the outside edge of the image forming layer sealing the gap between the top and bottom substrates.
A flexible circuit board is often used for the wiring board. The wiring board extends substantially along the display surface of the display panel from the end of the conductor portions of the display panel to which it is connected. The plural pins disposed to the other end of the wiring board are connected to a device-side circuit board by connectors.
In the construction of the related art in which the display panel and wiring board are connected between the plane surfaces thereof, a substrate connection portion for connecting the display panel and the wiring board is required outside the image display area of the display panel.
This substrate connection area must be outside the sealing member for reasons including conduction stability, and the size of the frame area surrounding the image display area is increased by the size of this seal plus the size of the substrate connection area. This degrades the appearance and increases the size of the device in which the display device is incorporated by the area of this frame.
Because the display module including the top substrate, image forming layer, and back substrate is separate from the wiring board, the housing structure for the display module and wiring board each take up space inside the device. This is particularly disadvantageous in devices in which space is at a premium, such as in a wristwatch.
In order to save space the flexible wiring board connected to the pins of the display panel could be folded over to overlap the back side of the display panel. However, the wiring board can only be folded over in this manner when the display panel and wiring board are sufficiently separated, and this actually requires even more space.
Because the wiring board and display panel are connected in the plane direction, the pins on the main circuit board of the device disposed on the back side of the display panel and the pins of the wiring board must normally be connected together by connectors. This means that the pin positions of the display device must correspond to the pin positions of the device, and wide applicability is thus impaired.
Furthermore, when the pins of the wiring board and the pins of the device-side circuit board are connected by individual connectors, connecting and disconnecting the wiring board from the device-side circuit board during initial assembly and after-sale service is difficult.